1. Field of the Invention
The present invention relates to a heat sensitive recording material, and more particularly, to a heat sensitive recording material, comprising a substrate having thereon a heat sensitive recording layer and a protective layer, which protective layer is excellent in transparency, gloss, heat resistance, and light fastness and simultaneously excellent in sliding properties and lubricating properties, which does not cause adhesion and trash deposition on a thermal head and the like and provides excellent color-developed images.
2. Description of the Related Art
Heat sensitive recording has recently begun to expand due to the recording apparatus used being simple, having high reliability, and requiring no maintenance. As the heat sensitive recording material used in this method, a material which utilizes a reaction of an electron donative colorless dye with an electron acceptive compound, a material which utilizes a reaction of a diazonium salt compound with a coupler, and the like are conventionally widely known.
Recently, intense research has been carried out to try and improve characterictics such as (1) color developing density and color developing sensitivity, (2) the fastness of a color developed material, and the like, of heat sensitive recording materials. However, when the heat sensitive recording material is exposed to sunlight for a long period of time, or is displayed in an office or the like for a long period of time, the background region of the heat sensitive recording material becomes colored and the image region changes or loses its color. Various methods have been suggested for improving this coloring of the background region and the changes in or loss of color in the image region of the heat sensitive recording material, however, satisfactory results have not always been obtained.
On the other hand, demands for a heat sensitive recording system have been expanded in a number of fields such as for facsimiles, printers, labels and the like. At the same time, friction resistance between the heat sensitive recording paper and the heat sensitive recording head, friction resistance in the rear surface of the paper, and the like are required. Conventionally, waxes (for example, zinc stearate and the like), matting agents, pigments and the like are used for imparting lubricating properties and friction resistance to a heat sensitive recording material. However, when these means are used, the friction resistance and lubricating properties are not always satisfactory, further, the transparency and gloss of a heat sensitive recording material are reduced, and these components are fused to the thermal head and the like to cause trash deposition, gloss unevenness and the like.